The object of these studies are to explore pituitary glucocorticoid negative feedback, with an emphasis on fast feedback in depression. These studies test the response of corticotrophs to two different secretagogues, corticotropin releasing factor and arginine vasopressin, following the removal of glucocorticoid negative feedback by metyrapone blockade with metyrapone as well as the re-introduction of negative feedback by infusion of cortisol in a controlled fashion.